The present invention is related to a copending Reissue application Ser. No. 534,745, now Pat. No. RE29022, application Serial No. 529,712 now abandoned and to U.S. Pat. No. 3,693,888. In the development of flush-drip irrigation emitters, difficulty has been experienced in insuring that the emitters can be depended upon to shift from flush to drip mode. This problem exists principally in agricultural use because it is desirable to have the maximum number of drip outlets in a flow line of minimum size and to maintain a minimum pump capacity; whereas, to insure successful flush to drip conversion, increased pump capacity has been required or the use of flat hose such as disclosed in U.S. Pat. No. 3,779,468, has been needed. To date, the extra cost has been a detering factor.